RAWALPINDI: The Civil Aviation Authority (PCAA) has issued notices to airmen of all aircraft, asking them to report to the air traffic controller (ATC) about any disturbances in GPS signals after signal interruptions were reported by aircraft.

The notices were issued to airlines, Pakistan Airline Pilots Association, IATA and others on September 22 and will remain valid till December 21.

It had been observed that aircraft were facing disturbances in getting GPS signals between Lahore and Karachi flight region. The aircraft were also having difficulties getting GPS signals between Lahore and Karachi flight information region (FIR).

The notices said occasional GPS signal interruptions had been reported around Lahore in a 100-nautical-mile radius, around the Lahore area in the sector south of Lahore, and also in some portions of Karachi FIR.

There were also complaints about not getting GPS signals around Rahimyar Khan airport.

Notices issued after reports about aircraft facing disturbances in getting GPS signals between Lahore and Karachi

“All pilots should promptly report to the Air Traffic Control (ATC) about such interruptions with appropriate details.”

It said that in the event, take necessary measures for safe and efficient continuation of navigation, and in case of navigational difficulty, notify ATC for assistance.

Meanwhile, the CAA said that Pakistan Airspace was fully covered with state-of-the-art radar systems for the provision of air traffic services to all aircraft, including transit, landing and taking off.

A spokesman for the CAA said that all equipment provided by the CAA were ground-based for which VOR (VHF omnidirectional range) was a navigation aid that provides azimuth information for high and low-altitude routes and airport approaches.

On the other hand, another ground-based equipment called ILS (instrument landing system) is a precision runway approach aid to provide pilots with vertical and horizontal guidance during the landing.

As far as GPS (global positioning system) is concerned, it’s a USA-owned utility that provides users with positioning, navigation and timing (PNT) services. GPS is a network of satellites and currently 31 GPS satellites are orbiting around the earth, providing users with accurate information on position, velocity, and time anywhere in the world.

There may be a reason for a space weather event (ionospheric disturbance) that may impact GNSS (global navigation satellite system) performance, possibly leading to the loss of GNSS signals and/or degradation of timing and positioning performance. This ionospheric activity has no link to any ground-based equipment, said the spokesman.

Published in Dawn, September 25th, 2023